Parallel excitation for B-field insensitive fat-saturation preparation.

Abstract

Multichannel transmission has the potential to improve many aspects of MRI through a new paradigm in excitation. In this study, multichannel transmission is used to address the effects that variations in B(0) homogeneity have on fat-saturation preparation through the use of the frequency, phase, and amplitude degrees of freedom afforded by independent transmission channels. B(1) homogeneity is intrinsically included via use of coil sensitivities in calculations. A new method, parallel excitation for B-field insensitive fat-saturation preparation, can achieve fat saturation in 89% of voxels with M(z) ≤ 0.1 in the presence of ± 4 ppm B(0) variation, where traditional CHESS methods achieve only 40% in the same conditions. While there has been much progress to apply multichannel transmission at high field strengths, particular focus is given here to application of these methods at 1.5 T.